1. What is a PCB Voltage Drop Calculator?

Definition: This calculator estimates the voltage drop across a PCB trace based on current, material resistivity, trace length, and cross-sectional area.

Purpose: It helps electronics designers ensure proper voltage levels reach components by accounting for trace resistance.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( VD \) — Voltage drop (volts)
• \( I \) — Current through the trace (amps)
• \( \rho \) — Resistivity of trace material (Ω·m)
• \( L \) — Length of the trace (meters)
• \( A \) — Cross-sectional area of the trace (m²)

Explanation: The voltage drop increases with higher current, longer traces, or narrower traces, and depends on the conductor material's resistivity.

3. Importance of Voltage Drop Calculation

Details: Proper voltage drop estimation ensures components receive adequate voltage, prevents signal integrity issues, and helps avoid excessive power loss.

4. Using the Calculator

Tips: Enter the current in amps, material resistivity (default 1.68×10⁻⁸ Ω·m for copper), trace length in meters, and cross-sectional area in square meters.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical resistivity value for copper?
A: Pure copper at 20°C has ρ ≈ 1.68×10⁻⁸ Ω·m. This increases with temperature (about 0.4% per °C).

Q2: How do I calculate trace cross-sectional area?
A: Multiply trace width by thickness (e.g., 0.2mm × 0.035mm = 7×10⁻⁹ m²).

Q3: What's an acceptable voltage drop?
A: Typically less than 3-5% of supply voltage, but depends on application requirements.

Q4: Does this account for temperature effects?
A: No, for high-temperature operation, increase the resistivity value accordingly.

Q5: How can I reduce voltage drop?
A: Use shorter/wider traces, thicker copper, or higher conductivity materials.